We write tests to ensure that the code that we wrote does what we expect it to do. Code is constantly changing, and to ensure that the assumptions that were valid when we wrote the code are still true today we need tests to check our code. Tests make our code more reliable, they ensure that working code keeps working which ultimately allows us to move faster.
Snapshot tests test the rendering of a component with a given set of inputs, due to the functional composition style of react components this tests almost always test other components. Because of the long dependency chain snapshot tests should give us signal about what's changing across our code. We should look at the differences between the snapshot and what was updated, but we don't need to be scared of updating our snapshots. The changes in the snapshot give us a history of how the component changed over time which can be useful when investigating code changes for debugging.
Running all tests in the https://github.com/invisible-tech/invisible repository
nx affected:test or nx run-many --all --target=test
This should create a coverage report in the coverage directory in the root directory of the invisible repo.